I scored 443 gate 2019 in mechanical branch AIR 15803, can I get NITs or IITs in material science? pls suggest

You have a fair chance to get a seat in most of the IITs and NITs as well provided you stick to M.Tech in Material Sciences. But your chances are subject to this year's trend. Like for example you have a good chance to make through IIT BHU or IIT Gandhinagar, you also have borderline chances of getting into into IIT Kharagpur since the GATE cut off for material science at IIT Kharagpur approximately hovers around 430.
Similarly you can try for most of the new IITs and NITs as well, you have decent chances of breaking through one of them.